1. Field of the Invention
The present invention relates to an opening/closing device and more specifically, to an opening/closing device which moves a movable plate with respect to a fixed plate.
2. Description of the Related Art
Generally, a mobile terminal device includes a first housing to which a numeric keypad, a liquid crystal display device or the like is provided and a second housing to which a liquid crystal display device or the like is provided and capable of being opened and closed with respect to the first housing. Further, as a structure which opens and closes the second housing with respect to the first housing, a folding type in which the first housing and the second housing are connected by a hinge mechanism so that the second housing is rotated with respect to the first housing and a slide type in which the second housing is slid with respect to the first housing are generally used.
Recently, a mobile terminal device has been progressed to have a multifunction, there is provided a device which is capable of receiving Digital Terrestrial Television Broadcasting and the size of the liquid crystal display device has been enlarged. Further, in accordance with providing the multifunction, the number of keys of the keyboard for performing an input process to the mobile terminal device tends to increase so that the size of the keyboard is becoming larger. On the other hand, for the mobile terminal device, improvement of the portability is always desired so that there is a limitation in enlarging the size of the liquid crystal display device and the keyboard.
For the above described folding type mobile terminal device, when the device is folded, the liquid crystal display device is closed so that there is a problem that the liquid crystal display device cannot be used in the folded state. Further, for the slide type mobile terminal device, although the same problems of the folding type do not occur, there is inevitably an overlapping between the first housing and the second housing at an opened state so that space cannot be efficiently used.
Thus, an opening/closing device at which the first housing and the second housing are positioned at the same plane (flat) when the first housing and the second housing are opened has been suggested (see Patent Documents 1 to 3). With this structure, the liquid crystal display device can be used even when the first housing and the second housing are closed, and there is no overlapping between the first housing and the second housing when they are opened to efficiently use a space.